The invention relates to a broad band switching system for the selective connection of broad band signal sources to subscribers receiving broad band signals, said connection being via a broad band switching network in which the crosspoint or coupling point circuits, whose function is to selectively connect input lines to output lines of the switching network, can be formed by means of linkage elements realized in ECL technology with a view to the smallest possible switching times or, respectively, to the, preferably, pulse-modulated signals with signal frequencies of, for example, up to more than 80 MHz to be through-connected (cf. Pfannschmidt: "Arbeitsgeschwindigkeitsgrenzen von Koppelnetzwerken fur Breitband-Digitalsignale", Diss. TU Bswg. 1978; German AS 2,828,662).
With such a broad band switching network, for example, television programs can be relayed to subscribers who wish to receive such programs, as is involved in more recent developments of telecommunications which lead to broad band communication networks with subscriber lines formed by means of light waveguides, whereby a star network of light waveguides with one light waveguide per dwelling unit proves favorable at the subscriber level, said light waveguide connecting a broad band switching location (preferably, spatially united with the nearest telephone switching location) to the dwelling of the subscriber and via which all telecommunication services are sequenced for the appertaining dwelling, whereby offering at least approximately the following communication possibilities comes into question, for example, for a dwelling connection which does justice to future developments:
three video channels for three video receivers with independent access to all television signal sources which can be reached by the switching location or, respectively, to all television programs available in the switching location, three return channels for program selection and, under certain conditions for developing interactive services, as well as a greater plurality of VHF radio channels (stereo) (ntz 32 (1979)3, pages 150 through 153).
Given such a television program exchange, it is not only that a plurality of subscriber terminals must be able to be simultaneously connected to one and the same program source, but, rather, vice versa, one and the same subscriber terminal must also be able to be simultaneously connected to a plurality of program sources. The invention reveals a way of doing justice to this in an expedient, cost-saving manner.